nevi-me commented on a change in pull request #7324: URL: https://github.com/apache/arrow/pull/7324#discussion_r435071238
########## File path: rust/arrow/src/compute/kernels/concat.rs ########## @@ -0,0 +1,395 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Defines concat kernel for `ArrayRef` +//! +//! Example: +//! +//! ``` +//! use std::sync::Arc; +//! use arrow::array::{ArrayRef, StringArray}; +//! use arrow::compute::concat; +//! +//! let arr = concat(&vec![ +//! Arc::new(StringArray::from(vec!["hello", "world"])) as ArrayRef, +//! Arc::new(StringArray::from(vec!["!"])) as ArrayRef, +//! ]).unwrap(); +//! assert_eq!(arr.len(), 3); +//! ``` + +use std::sync::Arc; + +use crate::array::*; +use crate::datatypes::*; +use crate::error::{ArrowError, Result}; + +use TimeUnit::*; + +/// Concatenate multiple `ArrayRef` with the same type. +/// +/// Returns a new ArrayRef. +pub fn concat(array_list: &Vec<ArrayRef>) -> Result<ArrayRef> { + let mut data_type: Option<DataType> = None; + let array_data_list = &array_list + .iter() + .map(|a| { + let array_data = a.data_ref().clone(); + let curr_data_type = array_data.data_type().clone(); + match &data_type { + Some(t) => { + if t != &curr_data_type { + return Err(ArrowError::ComputeError( + "Cannot concat arrays with data type".to_string(), + )); + } + } + None => { + data_type = Some(curr_data_type); + } + } + Ok(array_data) + }) + .collect::<Result<Vec<ArrayDataRef>>>()?; + + let data_type = match data_type { + None => { + return Err(ArrowError::ComputeError( + "Cannot concat 0 array".to_string(), + )); + } + Some(t) => t, + }; + match data_type { + DataType::Utf8 => concat_raw_string(array_data_list), + DataType::Boolean => concat_primitive::<BooleanType>(array_data_list), + DataType::Int8 => concat_raw_primitive::<Int8Type>(array_data_list), + DataType::Int16 => concat_raw_primitive::<Int16Type>(array_data_list), + DataType::Int32 => concat_raw_primitive::<Int32Type>(array_data_list), + DataType::Int64 => concat_raw_primitive::<Int64Type>(array_data_list), + DataType::UInt8 => concat_raw_primitive::<UInt8Type>(array_data_list), + DataType::UInt16 => concat_raw_primitive::<UInt16Type>(array_data_list), + DataType::UInt32 => concat_raw_primitive::<UInt32Type>(array_data_list), + DataType::UInt64 => concat_raw_primitive::<UInt64Type>(array_data_list), + DataType::Float32 => concat_raw_primitive::<Float32Type>(array_data_list), + DataType::Float64 => concat_raw_primitive::<Float64Type>(array_data_list), + DataType::Date32(_) => concat_raw_primitive::<Date32Type>(array_data_list), + DataType::Date64(_) => concat_raw_primitive::<Date64Type>(array_data_list), + DataType::Time32(Second) => { + concat_raw_primitive::<Time32SecondType>(array_data_list) + } + DataType::Time32(Millisecond) => { + concat_raw_primitive::<Time32MillisecondType>(array_data_list) + } + DataType::Time64(Microsecond) => { + concat_raw_primitive::<Time64MicrosecondType>(array_data_list) + } + DataType::Time64(Nanosecond) => { + concat_raw_primitive::<Time64NanosecondType>(array_data_list) + } + DataType::Timestamp(Second, _) => { + concat_raw_primitive::<TimestampSecondType>(array_data_list) + } + DataType::Timestamp(Millisecond, _) => { + concat_raw_primitive::<TimestampMillisecondType>(array_data_list) + } + DataType::Timestamp(Microsecond, _) => { + concat_raw_primitive::<TimestampMicrosecondType>(array_data_list) + } + DataType::Timestamp(Nanosecond, _) => { + concat_raw_primitive::<TimestampNanosecondType>(array_data_list) + } + DataType::Interval(IntervalUnit::YearMonth) => { + concat_raw_primitive::<IntervalYearMonthType>(array_data_list) + } + DataType::Interval(IntervalUnit::DayTime) => { + concat_raw_primitive::<IntervalDayTimeType>(array_data_list) + } + DataType::Duration(TimeUnit::Second) => { + concat_raw_primitive::<DurationSecondType>(array_data_list) + } + DataType::Duration(TimeUnit::Millisecond) => { + concat_raw_primitive::<DurationMillisecondType>(array_data_list) + } + DataType::Duration(TimeUnit::Microsecond) => { + concat_raw_primitive::<DurationMicrosecondType>(array_data_list) + } + DataType::Duration(TimeUnit::Nanosecond) => { + concat_raw_primitive::<DurationNanosecondType>(array_data_list) + } + t => unimplemented!("Concat not supported for data type {:?}", t), + } +} + +fn concat_primitive<T>(array_data_list: &Vec<ArrayDataRef>) -> Result<ArrayRef> +where + T: ArrowPrimitiveType, +{ + let rows_count = array_data_list.iter().map(|a| a.len()).sum::<usize>(); + let mut builder = PrimitiveBuilder::<T>::new(rows_count); + + for array_data in array_data_list { + let a = PrimitiveArray::<T>::from(array_data.clone()); + for i in 0..a.len() { + if a.is_valid(i) { + builder.append_value(a.value(i))?; + } else { + builder.append_null()?; + } + } + } + + Ok(Arc::new(builder.finish()) as ArrayRef) +} + +// for better performance, we manually concat primitive value buffers instead of using +// PrimitiveBuilder +fn concat_raw_primitive<T>(array_data_list: &Vec<ArrayDataRef>) -> Result<ArrayRef> +where + T: ArrowPrimitiveType, +{ + let value_count = array_data_list.iter().map(|a| a.len()).sum::<usize>(); + let mut null_count = 0; + let mut values_builder = BufferBuilder::<T>::new(value_count); + let mut null_bit_builder = BooleanBufferBuilder::new(value_count); + + for array_data in array_data_list { + null_count += array_data.null_count(); + let value_buffer = &array_data.buffers()[0]; + values_builder.write_bytes(value_buffer.data(), value_buffer.len())?; + for i in 0..array_data.len() { + null_bit_builder.append(array_data.is_valid(i))?; + } + } + + Ok(Arc::new(PrimitiveArray::<T>::from( + ArrayData::builder(T::get_data_type()) + .len(value_count) + .add_buffer(values_builder.finish()) + .null_count(null_count) + .null_bit_buffer(null_bit_builder.finish()) + .build(), + ))) +} + +// for better performance, we manually concat string value buffers instead of using StringBuilder +fn concat_raw_string(array_data_list: &Vec<ArrayDataRef>) -> Result<ArrayRef> { Review comment: Sorry, I meant slicing the second string array, something like below, which slices out "1" and "6" from the second array: ```rust fn test_concat_string_arrays() -> Result<()> { let arr = concat(&vec![ Arc::new( StringArray::try_from(vec![Some("hello"), Some("world")]) .expect("Unable to create string array"), ) as ArrayRef, // adding a comment for better visibility, slicing the array here StringArray::from(vec!["1", "2", "3", "4", "6"]).slice(1, 3), Arc::new( StringArray::try_from(vec![Some("foo"), Some("bar"), None, Some("baz")]) .expect("Unable to create string array"), ) as ArrayRef, ])?; let expected_output = Arc::new( StringArray::try_from(vec![ Some("hello"), Some("world"), // Some("1"), // removed by offset of 1 Some("2"), Some("3"), Some("4"), // Some("6"), // truncated by length of 3 Some("foo"), Some("bar"), None, Some("baz"), ]) .expect("Unable to create string array"), ) as ArrayRef; assert!( arr.equals(&(*expected_output)), "expect {:#?} to be: {:#?}", arr, &expected_output ); Ok(()) } ``` The same might need to be verified with numeric arrays because we write the whole data in `write_slice`, so if there's an offset, we might get unexpected outputs. I'll check your branch out locally and check this. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
